REST Assured Tutorial 31 – How To Create POJO Classes Of A Nested JSON Payload

As a part of End to End REST Assured Tutorial , in this post We will learn to create a POJO classes for a nested JSON payload.

We already know now :-

1. To create a POJO for a simple JSON Object Payload
2. To create a POJO for a simple JSON Array Payload

Now we will make it complex by nesting JSON Object and JSON arrays which we see in real time while working.

Example JSON Payload

{
  "companyName": "MSE",
  "companyHOCity": "Benagluru",
  "companyCEO": "Amod",
  "supportedSalaryBanks": [
    "HDFC",
    "ICICI",
    "AXIS"
  ],
  "pincodesOfCityOffice": [
    560037,
    360034,
    456343
  ],
  "employee": [
    {
      "firstName": "Amod",
      "lastName": "Mahajan",
      "gender": "Male",
      "age": 28,
      "salary": 10000.56,
      "married": false
    },
    {
      "firstName": "Animesh",
      "lastName": "Prashant",
      "gender": "Male",
      "age": 30,
      "salary": 20000.56,
      "married": false
    },
    {
      "firstName": "Kitty",
      "lastName": "Gupta",
      "gender": "Female",
      "age": 26,
      "salary": 30000.56,
      "married": false
    }
  ],
  "contractors": [
    {
      "firstName": "Seema",
      "lastName": "Singh",
      "contractFrom": "Jan-2019",
      "contractTo": "JAN-2025"
    },
    {
      "firstName": "Hari",
      "lastName": "Prasad",
      "contractFrom": "Jan-2017",
      "contractTo": "JAN-2030"
    }
  ],
  "companyPFDeails": {
    "pfName": "XYZ",
    "pfCity": "Benagluru",
    "pfYear": 2012,
    "noOfEmployees": 10
  }
}

Creating POJO classes are simple if we identify what are classes we need to create correctly. A final POJO class for a JSON Payload is created by combining multiple blocks. Let’s identify different objects or POJO :-

There is no need to create a POJO for a 1:1 fields. We can include them in a final POJO class. For example :- In above payload field names like “companyName” , “companyHOCity” and “companyCEO” are 1:1 mapped. Observe value of field name “supportedSalaryBanks“. It is kind of an array of strings which does not need a user defined class to represent specially. Similarly field name “pincodesOfCityOffice” has value as an array of integers. We can define above discussed field as below :-

private String companyName;
private String companyHOCity;
private String companyCEO;
private List supportedSalaryBanks;
private List pincodesOfCityOffice;

Now focus on field “employee” which has value as an array of employees. We do not have any ready made data type to represent element of this array as a whole. So here we need to create a POJO class which can contain all details of an employee. Create a simple POJO class to represent below data:-

{
      "firstName": "Amod",
      "lastName": "Mahajan",
      "gender": "Male",
      "age": 28,
      "salary": 10000.56,
      "married": false
}

To represent an array of employees :-

List employee;

Similar concept for field name “contractors”.

List contractors;

Field name “companyPFDeails” contains value as JSON object which is not present in Java. So we need to create a class for it like Employee above.

CompanyPFDeails companyPFDeails;

Once all building blocks are ready you need to create a final POJO class where all blocks will be kept together to represent whole payload.

Employee POJO Class

package RestfulBookerPojo;

public class Employee {

	// private variables or data members of pojo class
	private String firstName;
	private String lastName;
	private String gender;
	private int age;
	private double salary;
	private boolean married;
	
	// Getter and setter methods
	public String getFirstName() {
		return firstName;
	}
	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}
	public String getLastName() {
		return lastName;
	}
	public void setLastName(String lastName) {
		this.lastName = lastName;
	}
	public String getGender() {
		return gender;
	}
	public void setGender(String gender) {
		this.gender = gender;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public double getSalary() {
		return salary;
	}
	public void setSalary(double salary) {
		this.salary = salary;
	}
	public boolean getMarried() {
		return married;
	}
	public void setMarried(boolean married) {
		this.married = married;
	} 	
}

Contractors POJO Class

package RestfulBookerPojo;

public class Contractors {
	private String firstName;
	private String lastName;
	private String contractFrom;
	private String contractTo;
	
	public String getFirstName() {
		return firstName;
	}
	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}
	public String getLastName() {
		return lastName;
	}
	public void setLastName(String lastName) {
		this.lastName = lastName;
	}
	public String getContractFrom() {
		return contractFrom;
	}
	public void setContractFrom(String contractFrom) {
		this.contractFrom = contractFrom;
	}
	public String getContractTo() {
		return contractTo;
	}
	public void setContractTo(String contractTo) {
		this.contractTo = contractTo;
	}

}

CompanyPFDeails POJO Class

package RestfulBookerPojo;

public class CompanyPFDeails {
	private String pfName;
	private String pfCity;
	private int pfYear;
	private int noOfEmployees;
	
	public String getPfName() {
		return pfName;
	}
	public void setPfName(String pfName) {
		this.pfName = pfName;
	}
	public String getPfCity() {
		return pfCity;
	}
	public void setPfCity(String pfCity) {
		this.pfCity = pfCity;
	}
	public int getPfYear() {
		return pfYear;
	}
	public void setPfYear(int pfYear) {
		this.pfYear = pfYear;
	}
	public int getNoOfEmployees() {
		return noOfEmployees;
	}
	public void setNoOfEmployees(int noOfEmployees) {
		this.noOfEmployees = noOfEmployees;
	}
}

Final POJO class with all building blocks

package RestfulBookerPojo;

import java.util.List;

public class NestedPOJO {
	
	private String companyName;
	private String companyHOCity;
	private String companyCEO;
	private List supportedSalaryBanks;
	private List pincodesOfCityOffice;
	List employee;
	List contractors;
	CompanyPFDeails companyPFDeails;
	
	public String getCompanyName() {
		return companyName;
	}
	public void setCompanyName(String companyName) {
		this.companyName = companyName;
	}
	public String getCompanyHOCity() {
		return companyHOCity;
	}
	public void setCompanyHOCity(String companyHOCity) {
		this.companyHOCity = companyHOCity;
	}
	public String getCompanyCEO() {
		return companyCEO;
	}
	public void setCompanyCEO(String companyCEO) {
		this.companyCEO = companyCEO;
	}
	public List getSupportedSalaryBanks() {
		return supportedSalaryBanks;
	}
	public void setSupportedSalaryBanks(List supportedSalaryBanks) {
		this.supportedSalaryBanks = supportedSalaryBanks;
	}
	public List getPincodesOfCityOffice() {
		return pincodesOfCityOffice;
	}
	public void setPincodesOfCityOffice(List pincodesOfCityOffice) {
		this.pincodesOfCityOffice = pincodesOfCityOffice;
	}
	
	public List getEmployee() {
		return employee;
	}
	public void setEmployee(List employee) {
		this.employee = employee;
	}
	public List getContractors() {
		return contractors;
	}
	public void setContractors(List contractors) {
		this.contractors = contractors;
	}
	public CompanyPFDeails getCompanyPFDeails() {
		return companyPFDeails;
	}
	public void setCompanyPFDeails(CompanyPFDeails companyPFDeails) {
		this.companyPFDeails = companyPFDeails;
	}

}

Let’s create a JSON Payload using above POJO classes.

package RestfulBookerPojo;

import java.util.ArrayList;
import java.util.List;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class CreateNestedJSONFromPOJOClasses {

	public static void main(String[] args) throws JsonProcessingException {
			
		NestedPOJO nestedPOJO = new NestedPOJO();
		nestedPOJO.setCompanyName("MSE");
		nestedPOJO.setCompanyHOCity("Benagluru");
		nestedPOJO.setCompanyCEO("Amod");
		
		List supportedSalaryBanks = new ArrayList();
		supportedSalaryBanks.add("HDFC");
		supportedSalaryBanks.add("ICICI");
		supportedSalaryBanks.add("AXIS");
		nestedPOJO.setSupportedSalaryBanks(supportedSalaryBanks);
		
		List pincodesOfCityOffice = new ArrayList();
		pincodesOfCityOffice.add(560037);
		pincodesOfCityOffice.add(360034);
		pincodesOfCityOffice.add(456343);
		nestedPOJO.setPincodesOfCityOffice(pincodesOfCityOffice);
		
		// Create first employee
		Employee amod = new Employee();
		amod.setFirstName("Amod");
		amod.setLastName("Mahajan");
		amod.setAge(28);
		amod.setGender("Male");
		amod.setSalary(10000.56);
		amod.setMarried(false);

		// Create second employee
		Employee animesh = new Employee();
		animesh.setFirstName("Animesh");
		animesh.setLastName("Prashant");
		animesh.setAge(30);
		animesh.setGender("Male");
		animesh.setSalary(20000.56);
		animesh.setMarried(true);

		// Create third employee
		Employee kitty = new Employee();
		kitty.setFirstName("Kitty");
		kitty.setLastName("Gupta");
		kitty.setAge(26);
		kitty.setGender("Female");
		kitty.setSalary(30000.56);
		kitty.setMarried(false);

		// Creating a List of Employees
		List allEMployees = new ArrayList();
		allEMployees.add(amod);
		allEMployees.add(animesh);
		allEMployees.add(kitty);
		nestedPOJO.setEmployee(allEMployees);
		
		Contractors seema = new Contractors();
		seema.setFirstName("Seema");
		seema.setLastName("Singh");
		seema.setContractFrom("Jan-2019");
		seema.setContractTo("JAN-2025");
		
		Contractors hari = new Contractors();
		hari.setFirstName("Hari");
		hari.setLastName("Prasad");
		hari.setContractFrom("Jan-2017");
		hari.setContractTo("JAN-2030");
		
		List allContractors = new ArrayList();
		allContractors.add(seema);
		allContractors.add(hari);
		nestedPOJO.setContractors(allContractors);
		
		CompanyPFDeails companyPFDeails = new CompanyPFDeails();
		companyPFDeails.setPfName("XYZ");
		companyPFDeails.setPfCity("Benagluru");
		companyPFDeails.setPfYear(2012);
		companyPFDeails.setNoOfEmployees(10);
		nestedPOJO.setCompanyPFDeails(companyPFDeails);
		
		ObjectMapper objectMapper = new ObjectMapper();
		String nestedJsonPayload = objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(nestedPOJO);
		System.out.println(nestedJsonPayload);
	}
}

Output

{
  "companyName" : "MSE",
  "companyHOCity" : "Benagluru",
  "companyCEO" : "Amod",
  "supportedSalaryBanks" : [ "HDFC", "ICICI", "AXIS" ],
  "pincodesOfCityOffice" : [ 560037, 360034, 456343 ],
  "employee" : [ {
    "firstName" : "Amod",
    "lastName" : "Mahajan",
    "gender" : "Male",
    "age" : 28,
    "salary" : 10000.56,
    "married" : false
  }, {
    "firstName" : "Animesh",
    "lastName" : "Prashant",
    "gender" : "Male",
    "age" : 30,
    "salary" : 20000.56,
    "married" : true
  }, {
    "firstName" : "Kitty",
    "lastName" : "Gupta",
    "gender" : "Female",
    "age" : 26,
    "salary" : 30000.56,
    "married" : false
  } ],
  "contractors" : [ {
    "firstName" : "Seema",
    "lastName" : "Singh",
    "contractFrom" : "Jan-2019",
    "contractTo" : "JAN-2025"
  }, {
    "firstName" : "Hari",
    "lastName" : "Prasad",
    "contractFrom" : "Jan-2017",
    "contractTo" : "JAN-2030"
  } ],
  "companyPFDeails" : {
    "pfName" : "XYZ",
    "pfCity" : "Benagluru",
    "pfYear" : 2012,
    "noOfEmployees" : 10
  }
}

Note – I have used Jackson Java library to convert a Java object to String. Make sure you have latest dependency added. For this example I have used below maven dependency : –

   com.fasterxml.jackson.core
   jackson-databind
   2.11.0

You can download/clone above sample project from here.

If you have any doubt, feel free to comment below.
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